Use a transistor to control a larger current or voltage than the Arduino can handle. Use the Arduino to control the transistor, and the transistor to control the load. Choose the power supply voltage to match the voltage needed by the external load. Choose the power...

Ever since I learned that 3D printers were at thing, I’ve wanted to do this. I designed a socket wrench holder for 3/8 drive fractional sockets. It will stack with others in this design series. I included the fused filament printer support in the design file so...